Why? Move on from Kyrie, and pick up Kemba. Kemba is the type of player who can adapt to any style of play with ease. And I'd take Kemba over Brown any day of the week.
If somehow they could swing it, I'd pick up Kemba and Anthony Davis, and move on from Kyrie, Heyward, and Brown (would require it at min). Kemba/AD/Tatum/Horford plus whomever else (Smart and co.) would freakin dominate.
I don't believe in 'too much talent'. It's slow to come together this year, but that was to be expected. You don't just change a team around completely, especially inserting the team leader and ball dominant player, along with a guy who isn't quite there yet both mentally and physically, and expect it to go smoothly.
I expect them to be a machine come playoff time.